1. Field of the Invention
The present invention relates to gas purge of a container in which semiconductor substrates or the like are accommodated.
2. Description of the Related Art
Articles such as semiconductor substrates or reticles are accommodated in a container such as a FOUP or a reticle pod, and the container is transported by a transporting device and is stored in a stocker, an automated warehouse, or the like. In this regard, a purge gas such as nitrogen gas or clean dry air is supplied from a nozzle into the container via a gas inlet part in order to prevent contamination and oxidation of the articles and the like. The gas inlet part is made of, for example, an elastic circular material and has a hole in the center. With respect to the supply of the purge gas, JP2012-248785 proposes introducing the purge gas into a container via a nozzle configured to move up and down with an air cylinder.
In JP2012-248785, the contact pressure between the nozzle and the gas inlet part is maintained in a substantially constant range due to the air pressure applied by the air cylinder. On the other hand, if a fixed nozzle is put in contact with the gas inlet part of the container, the contact pressure changes due to a variation in the weight of the container depending on, for example, the presence or absence of semiconductor substrates, a variation in the height of the gas inlet part, or the like. Furthermore, the increases in the sizes of the semiconductor substrates have increased the weights of the containers. Therefore, pressed marks of the nozzle often remain on the surface of the gas inlet part made of an elastic material, and the gas inlet part often gets scratched. If the gas inlet part gets the nozzle mark or the scratches caused by the nozzle, the purge gas may leak due to the nozzle mark or the scratches caused by the nozzle on the gas inlet part, when the container has been transported and is newly put in contact with another nozzle. Furthermore, the gas inlet part and the nozzle are sometimes caught by each other due to the nozzle mark or the scratch caused by the nozzle, the container is prevented from sliding, and this possibly causes a failure in positioning of the container.